1. Field of the Invention
The invention pertains to an airbag.
2. Prior Art
Airbag devices of the type described herein are generally known from the prior art. Motor vehicle airbag devices of this type have at least one cover flap, behind which is a gas generator with which a gas bag can be inflated, and also moving drive devices which can be actuated by and are connected to each cover flap, where the latter is moved before or during the triggering of the gas generator within the airbag device or within a part of the motor vehicle containing the airbag device.
The objective of the present invention is to further improve this type of airbag device, which already has significant favorable properties and functions well.
To achieve this goal, the invention provides for an airbag device with the properties as herein described.
Therefore, according to the present invention, an airbag device for a motor vehicle is provided with at least one cover flap, and behind which is situated a gas generator with which a gas bag can be inflated. Moving drive devices are connected to each cover flap for movement before or during the triggering of the gas generator within the airbag device or within a part of the motor vehicle containing the airbag device. The invention provides that the drive devices contain at least one piston running within a channel.
Since the corresponding airbag flap mechanism is used particularly on the passenger side of a motor vehicle, the invention contributes toward a further increase in passenger safety, for example. In addition, in the present invention it is preferred that the airbag device be of modular embodiment or that it be a complete module.
In refinement of the invention, drive pressure generating devices are provided that contain the gas generator and/or gas generator devices separate from it.
Preferably, in an airbag device according to the present invention, the drive pressure generating devices are sealed gastight to the channel, and the piston is a pressure vessel sealed against the channel and the drive pressure generating devices. In this case, the drive pressure generating devices can be formed by the gas generator.
In a preferred refinement of the present invention, control devices are provided that guide the compressed gas generated by the gas generator into the gas bag as soon as the pressure vessel has reached a specified position in the channel. This can be achieved in that the control devices contain gas leadthroughs to the gas bag that pass through the channel wall, where said gas leadthroughs are released as soon as the pressure vessel has reached a specified position in the channel. Alternatively, it is also possible that the control devices contain gas leadthroughs to the gas bag that pass through the channel wall and also passage openings through the pressure vessel wall, and that the gas leads through the channel wall and the passage openings through the pressure vessel wall are aligned in the channel in a specified position of the pressure vessel and release a gas discharge into the gas bag.
In an additional refinement of the invention, the channel is formed by a guide vessel within which the piston runs.
Furthermore, with regard to an airbag device according to the present invention, it is preferred that the housing of the gas generator, the channel and/or the piston be made of sheet metal or as an extruded section.
Furthermore, with regard to an airbag device according to the present invention, it is provided that the drive devices contain at least two pistons running within one channel or each within a single channel. Within the framework of the invention, this attribute can be refined in that the pistons are coupled for synchronized movement of all pistons. In this regard it is possible that each piston be coupled to a toothed rack for synchronized movement of all pistons and that all toothed racks engage with gear devices.
An additional advantage of the present invention provides that each cover flap of the airbag device and a vehicle part surrounding the cover flap in its closed position contain a common cover layer and that disconnection devices be provided that weaken or disconnect the cover layer at least approximately and partially along its perimeter before or during a movement of each cover flap.
In another refinement of the airbag device according to the present invention, the gas bag is folded before triggering of the airbag device so that during introduction of a gas, it will inflate at least essentially outwardly from the middle.
Preferably, the gas generator is a multi-stage gas generator.
In addition, in the airbag device according to the present invention, it is preferred that a piston be coupled by means of pulling elements to at least one cover flap.
In another favorable refinement of the invention, guide rings are provided for each cover flap.
Additional favorable configurations of the invention will be specified below.
The generator of the airbag device within the framework of one embodiment is produced preferably from steel. It is encased on the side with the pressure vessel with a guide vessel as a channel and is connected by welding or clinching, e.g., there is a pressure vessel as piston running in the guide vessel and it is thus supported over a large area and sealed. The guide vessel and pressure vessel each consist of a middle part and two front walls of shaped sheet metal. The three parts are each welded at the corners. With regard to the guide vessel, the front walls can also be overlapped with a flange and clinched.
The generator of the airbag device can alternatively be made of extruded, light metal. If necessary, two generator stages as chambers can be each introduced with series-connected noise-particle-and fire-absorption chambers. Also, the attachment of the airbag material is integrated with the guide vessel, just like a guide and support of the pressure vessel. Gas passage holes and propellant openings are installed with xe2x80x9cscissorsxe2x80x9d tools. The front sides consist preferably also of extruded parts to guide the pressure vessel and for attachment of the bag. After welding of the xe2x80x9cpressure coverxe2x80x9d they will also preferably be sealed shut. To seal off and to guide the pressure vessel, four additional, extruded corner pieces can be used, for example, which can likewise be welded on.
Based on experiments, it can be readily determined whether the pressure vessel in actual cases of use should be coated, with POM for example, to simplify or promote unhindered sliding, and whether at its upper edge an additional gasket opening under pressure should be provided (see FIG. 4).
At the end of the movement of the pressure vessel in the guide vessel, gas passage holes, or more precisely gas leadthroughs, for example, through the channel wall and the passage openings through the pressure vessel wall to the cover come to coincide and allow the gas that was used to move the pressure vessel to flow into the bag and be inflated in a first step.
In the airbag generator, for example, for the passenger side, according to another embodiment preferably integrated, opposing pistons can be installed, whose pyrotechnic pressurization generates a force that moves the airbag flap(s). In this case, a pyrotechnic cartridge between the pistons, for example, will be ignited. The ignition of the pyrotechnic cartridge also ignites the propellant, e.g., of a first stage of the airbag generator. In order for both pistons to operate synchronously, a gear wheel is installed between them (see FIGS. 6 and 7), into which the pulling elements formed as gear rack engage as a kind of spring steel strip. Thus, the movement of the pistons is synchronized via the gear rack and engage with the central wheel.
Additional preferred and favorable configurations of the invention are obtained from the teachings herein.